Convert SQL Update statement to run in Access VBA

I have the following update query that runs in SQL. I need to convert it to VBA and run it in Access 2007. Apparently CONVERT, FLOOR and FLOAT are not valid VBA functions and I'm struggling with what and how to replace them with VBA equivalents. Any help would be greatly appreciated.

UPDATE A
SET A.Exp_Date = (SELECT CONVERT(DATETIME, FLOOR(CONVERT(FLOAT,ISNULL(DATEADD(DD, -1, MIN(A2.Due_Date)),GETDATE()))))FROM @ArmEff A2 WHERE A2.Due_Date > A.Due_Date)
FROM @ArmEff A